Effects of hyperlipidemias in hamsters on lipid transfer protein activity and unidirectional cholesteryl ester transfer in plasma

Experiments were performed to characterize plasma lipid transfer protein activity (LTA), and the rate of [3H]CE transfer from HDL to lower density lipoproteins in plasma of hamsters. Compared to rabbits, hamster plasma has about one-tenth the level of d greater than 1.21 LTA but a relatively high level of VLDL-triacylglycerols, and a higher fractional rate of HDL-[3H]CE transfer in plasma (in vitro) than predicted by the d greater than 1.21 LTA. Like the rat, hamster plasma contains an inhibitor(s) of LTA; the level of the inhibitor activity in d greater than 1.21 g/ml plasma was similar in normal and hyperlipoproteinemic hamsters. Hypertriglyceridemia in sucrose-fed hamsters did not affect LTA, cholesteryl ester transfer or the plasma level of HDL-CE. However, a comparable degree of hypercholesterolemia was associated with a 122% increase in plasma d greater than 1.21 LTA and a 63% increase in the fractional rate of [3H]CE transfer from HDL to lower density lipoproteins in plasma. Cholesterol feeding in hamsters was associated with increased plasma levels of LDL-cholesterol and, to a lesser extent, with VLDL- and IDL-cholesterol.